If a person has, for example, osteoporosis due to rarefied bone density, in some cases, he or she may suffer a wrist fracture (distal radius fracture) by putting his or her hand on something when falling down. Currently, treatment for the distal radius fracture has adopted a plate fixing technique in which a plate (mainly a locking plate) is arranged so as to cross from a fractured main bone piece to a peripheral bone piece, and the plate and each bone are repositioned and fixed by a screw. However, since the plate is installed outside the bone, there is a possibility that the screw or an end portion of the plate may damage surrounding tissues (flexor tendon, extensor tendon, or the like). In addition, there are some medical cases in which it is necessary to remove the screw from the plate in order to avoid complications such as tendon rupture and the like. In this case, it is necessary to carry out surgery by incising the skin twice, when the plate is installed and when the screw is removed.
Therefore, in the treatment for the bone fracture, treatment which is less invasive and has fewer complications is required. For example, as disclosed in Japanese Application Publication No. 2006-505339 (JP-T-2006-505339), a method is proposed in which a bone filling material is placed inside the bones so as to promote osteosynthesis. A device disclosed in Japanese Application Publication No. 2006-505339 Japanese Application Publication No. 2006-505339 includes a balloon configured to have a bioabsorbable material in a distal end portion of the device. During the treatment, the balloon filled with the bone filling material is placed inside the bone. If the balloon is absorbed into a living body after the placement, the bone filling material cured inside the balloon is exposed, and supports a bone fracture site from the inside of the bone instead of the plate or the screw in the previously described plate fixing technique. In this manner, the osteosynthesis is promoted.